(Normally, this isn't the kind of review I would leave. I would talk about the way the story is conveyed, talk about the message, get a little artsy at times, give helpful pointers when I'm able to...)
I loved how the movie drew me in immediately. Everything's great: The pacing, the animation, the characters' expressions... I mean: It's an _eye_! One character is essentially _an_eye_ and with just a few lines you made it emote so clearly and strongly.
I'm a pretty silent person, but at some point I exclaimed: "Oh, this is nice. This is _actually_ nice!"
And all that from just 'a trailer'. I'm looking forward to the release of 'Koishi Project', no matter if it's this year, the next, or 2050... If I wasn't already following you I would be 'now'. :)
I already suspect that the greatest tragedy of its release will be that we cannot rate it higher than 5 stars.
Edit: @Xenomorphian: Just wanted to confirm: You are absolutely correct. I just know "Touhou" as "a thing that has fanart done from time to time", so I have little to no chance recognizing any of it when I see it. Since it doesn't change my initial reaction as an uninformed person, I'll leave the rest of my review as is, though. ;)